This is the clearest and best demonstration of checking Mosfets I've found so far. Good on you for taking the time and trouble to do this for mugs like me! My search is over, I'm now confident in doing this.
this video is 6 years old as i watched it today, even six years after posting it it still helping people. thats brilliant, thank you i am more wiser on testing mosfet now.
Thanks for showing how to do this with a known good mosfet and a bad one..no more being confused by the other videos on how to test!! You won yourself a subscriber!!
I had a trailer brake controller which was constantly applying the trailer brakes even when the truck was off. Happened to find this video while googling the transistor number and found the transistor was shorted internally just like the one in this video. Thank you so much!!!
Thx a lot for your movie! Today I bought a simple china component tester! It make my live so easier! I don‘t soldering anything out and nothing! Clip on the wire measure in secounds, done! Perfect! 💪💪💪
Both of my meters are similar types (read the same way) as yours. Other videos show different readouts, and I was still confused. Now with yours, I know my MOSFET IS faulty. Thank you.
Oddly enough, I have a B&K component tester that shows 2.9vdc output on the diode setting but will NOT charge an IRF520. I have a Fluke digital multimeter that outputs only 2.5vdc on the diode setting but works perfectly on the SAME IRF520 every time.
An easy tester is a 9v battery with a single diode and led(with resistor if you want it, for indication) on one probe. Subtract the diode and led voltage and you got a simple polarity tester. (You still need a meter to measure voltage drop on it but got more than 2/3 volts to play with)😊
Many thanks for this tutorial. Just got some Mosfets off a Brushless motor ESC and found 2 duff and 4 working OK. I'm making a flashing 10W LED lamp to put in my model aircraft for when they go in to cloud or otherwise out of sight, and needed the mosfets to switch the power on and off to the LED driver.
simple and right to the point " that was a good way to demonstrate that ! Also if checking power mosfets with ohm meter set to ohms reading and you get ANY reading between any combination of gate to drain or source to gate ect that shows a dead short the mosfet is bad it's shorted ! but make sure to discharge it by holding the three leads between your finger and thumb before doing dead short test this way ! I have had many mosfets read .437 and ( point 437) work fine as that is residual capacitance in the internal circuit ! always check a new one before installing it !
Thanks for the help! Because of this video I found that a MOSFET I suspected to be bad turned out to be good. Ended up fixing a device which really had a bad electrolytic cap. Who would have guessed?
Thanks for this tutorial. It helped me fix a GPS problem (level shifter MOSFET was being uncooperative) with my HAB flight tracker for my dissertation.
awesome video.. the most simple and easy explanation on the internet.. everyone else seems to make it so difficult.. good job.. if u can show this on a laptop motherboard that would be very helpful .. thanks
I found this video informative and great to have produced. I forgot the charge up of source to drain part to develop a capacitive voltage for a short while in good MOSFETs. I would want to double check my schematics of the MOSFET to know where the source and drain are vs gate to drain shorts. I don't have a transistor checker multimeter yet.
THANK YOU ! you saved me a ton of trouble shooting !
4 года назад+3
Be aware that this works *only if* the voltage provided by the dmm to charge the gate is above the mosfet's gate threshold voltage. The high-voltage fets have Vgs-thr above 4V. Some even atound 10V. The low-signal and ultra-low voltage have lower voltages but not much below 4V. A regular dmm outputs about 1V...2V with high impedance. Some up to 8V on a 10Mohm load. It is safer to use a variable power supply with a high-value series resistor as s gate charger.
Thankyou for the tutorial. I have a Technic amplifer with an issue with high voltage. I think the Toshiba SK117 could be defective, the gate with the old part appears to be the center pin. I am getting low values on the Diode test 145 etc ( my meter is 3 diget), so i assume all must be defective. As i get no 1 (which is OL) on your meter
Great Info, Thank you! But for the sake of newbies like me, you should have explained as well how come touching the Red Probe of the meter (with the meter in Diode Test Mode) to the MOSFET Gate charges it (if you get my drift, that is). Thanks again.
build a simple tester with an old analog meter, or even a vu meter movement. use a 9 v bat. or two in series with a resister (to limit current to full scale deflection) and red and black alligator clips. clip across collector-emitter and activate base with just a finger from base to col. Same with MOSFETs. you can actually see the transistor switch off or on with a slight brush against the gate from either drain or source. sorry, cannot easily do a video of this but a very simple analog "super ohmmeter" demonstrates transistor,fet action. Also handy to confirm leakage of capacitors that digital meters miss.
I can't seem to get my fet to turn on .. it does have a 20-30v VGS rating though .. I'm assuming that's why, right ? Thanks for the video ! Very nice and clear !
Awesome video. I have a bad power board in my LG oled tv and I suspect one or two mosfets are burnt. Gonna use your method to test those. Thanks a bunch.
So, that mosfet that you are checking is a P-channel type because the Gate is at the positive probe?Am I correct? And how to determine of what pin is the Base, Drain, and Source by using only multimeter (diode mode) amd without looking the specification of that mosfet parts?
Excellent. Is it possible for you to do a video on " THYRISTOR (SCR) Testing using a Multimeter" as well? I would really appreciate it. I thank you in anticipation.
To test P Mosfets you do the same test but swap + and - (easier to just swap them at meter and do the same test) wish someone would have mentioned that to me before spending a fair bit of cash replacing both the N and P in a amp when both were fine.
great little video.. but i can't get any readings at all no matter what connections i make . the G, D and S are the same as in your video .. i am testing a STW80NE06-10 Mosfet .. . does this mean it's completly blown ..
This is a good start, unfortunately, a MOSFET can pass these tests and still be bad. You still need to check VF and RDS for example which can be significantly off and still pass these tests shown here.
Good video but I have a question, I have a clamp meter 266FT with no diode test mode but it has ohm test labeled 2M, 20K and continuity test labeled 200. Can I use it to test Transistors? Or I should purchase another multimeter
Thank You Good tutorial..
+Tuan Sathiyan You're welcome. Thanks for the nice comment! Please like and subscribe!
+Runforlife ,,,very clear explanation ,,,good channel!
thanks
Thanks!
This is the clearest and best demonstration of checking Mosfets I've found so far. Good on you for taking the time and trouble to do this for mugs like me! My search is over, I'm now confident in doing this.
it was so annoying with all the other videos until I found this
I got myself a transistor tester, but this method is still extremely valuable when you don't have access to other tools. Thank you.
this video is 6 years old as i watched it today, even six years after posting it it still helping people.
thats brilliant, thank you i am more wiser on testing mosfet now.
Thanks for showing how to do this with a known good mosfet and a bad one..no more being confused by the other videos on how to test!! You won yourself a subscriber!!
I had a trailer brake controller which was constantly applying the trailer brakes even when the truck was off. Happened to find this video while googling the transistor number and found the transistor was shorted internally just like the one in this video. Thank you so much!!!
That's worth a subscribe. So many videos, so technical from so many super smart dudes that could not correlate to me so easily as you have done ty
Watched the video, immediately tested my MOSFET. Thank you SO much for the information!
Thx a lot for your movie! Today I bought a simple china component tester! It make my live so easier! I don‘t soldering anything out and nothing! Clip on the wire measure in secounds, done! Perfect! 💪💪💪
Both of my meters are similar types (read the same way) as yours. Other videos show different readouts, and I was still confused. Now with yours, I know my MOSFET IS faulty. Thank you.
Masha-Allah. Zazakallah Khyer. You are very helpful for every engineering students.May you live a long life with Full of gladness and health.
perfect video, clear English & easy to comprehend
Nice video! Just a notice: most multimeter operates between 1V to 2V in diode tester mode which is not enough for a switching MOSFET to open.
Thanks for the info.
I saw a lot of videos and was wondering, Why my DMM can't charge Capacitor by touching the Gate.
Oddly enough, I have a B&K component tester that shows 2.9vdc output on the diode setting but will NOT charge an IRF520. I have a Fluke digital multimeter that outputs only 2.5vdc on the diode setting but works perfectly on the SAME IRF520 every time.
yeah some meters test with 7 Volt and some 3.5 V or lower etc, this needs to be checked first with another multimeter.
An easy tester is a 9v battery with a single diode and led(with resistor if you want it, for indication) on one probe. Subtract the diode and led voltage and you got a simple polarity tester. (You still need a meter to measure voltage drop on it but got more than 2/3 volts to play with)😊
Many thanks for this tutorial. Just got some Mosfets off a Brushless motor ESC and found 2 duff and 4 working OK. I'm making a flashing 10W LED lamp to put in my model aircraft for when they go in to cloud or otherwise out of sight, and needed the mosfets to switch the power on and off to the LED driver.
Excellent video mate, first class! You really do make it simple even for newbie's like me to understand and for that I thank you very much.👍
simple and right to the point " that was a good way to demonstrate that ! Also if checking power mosfets with ohm meter set to ohms reading and you get ANY reading between any combination of gate to drain or source to gate ect that shows a dead short the mosfet is bad it's shorted ! but make sure to discharge it by holding the three leads between your finger and thumb before doing dead short test this way ! I have had many mosfets read .437 and ( point 437) work fine as that is residual capacitance in the internal circuit ! always check a new one before installing it !
Thank you for sharing. Good explanatory and simple tools to test. Thank you again.
Man, I would just like to express my sincere thank you!
Thanks for the help! Because of this video I found that a MOSFET I suspected to be bad turned out to be good. Ended up fixing a device which really had a bad electrolytic cap. Who would have guessed?
A video well done. I design circuits, but did not have this test technique in my bag of tricks. Thank you.
+TheBdd4 Thanks for your comment! :)
Thanks a lot for teaching me how to test a mosfet hope i good learning more from you like other type of mosfet how to test thank you very much !
Awesome video for learning, also your way of explaining is well. Thanks brother-Pakistan
Thanks for this tutorial. It helped me fix a GPS problem (level shifter MOSFET was being uncooperative) with my HAB flight tracker for my dissertation.
Short and to the point, thank you!
This is a great tutorial, I have just tried this with my IRFZ44N Mosfet and it works perfect. I have liked and subscribed. Thank John.... :)
Great. Thanks for sharing!
THANK YOU. helped me figure out for the first time of my life if a mosfet it good or not! :D
awesome video.. the most simple and easy explanation on the internet.. everyone else seems to make it so difficult.. good job.. if u can show this on a laptop motherboard that would be very helpful .. thanks
Thanks, it's clear. But what about P-channel MOSFET? Is it the same way to test?
My question too 😁 do the test on P-channel! 👍
you need to reverse the Vgs voltage. red probe on source, black probe on gate
and you need to measure the connection from source to drain. red probe on source black probe on drain
I found this video informative and great to have produced. I forgot the charge up of source to drain part to develop a capacitive voltage for a short while in good MOSFETs. I would want to double check my schematics of the MOSFET to know where the source and drain are vs gate to drain shorts. I don't have a transistor checker multimeter yet.
On and Off state ...again learned something new... thx verry much.
good tutorial.at the beginning you have to short those pins with the negative lead but everything is correct.once again good job.
THANK YOU ! you saved me a ton of trouble shooting !
Be aware that this works *only if* the voltage provided by the dmm to charge the gate is above the mosfet's gate threshold voltage.
The high-voltage fets have Vgs-thr above 4V. Some even atound 10V.
The low-signal and ultra-low voltage have lower voltages but not much below 4V.
A regular dmm outputs about 1V...2V with high impedance. Some up to 8V on a 10Mohm load.
It is safer to use a variable power supply with a high-value series resistor as s gate charger.
Very simple and valuable explanation. Useful for beginners like me. Like to watch your other videos. Tanks.
Thanks, helped me test and prove a MOSFET in a Honda CBR indicator relay was good
Fantastic and educative video ❤❤❤❤🎉 excellent work bros.
Outstanding video. Very well explain and simple to understand! Keep it coming... 73, Joe-K4JGA - JGA Electronics Repair Center, Florida
tnx so much for sharing ung knowledge👍👍👍GODBLESS
Good video.How do you know that the first one is the gate,drain and last is source?
This is how you should do a tutorial short and to the point!
Thankyou for the tutorial. I have a Technic amplifer with an issue with high voltage. I think the Toshiba SK117 could be defective, the gate with the old part appears to be the center pin. I am getting low values on the Diode test 145 etc ( my meter is 3 diget), so i assume all must be defective. As i get no 1 (which is OL) on your meter
Saved me a ton of time. Thank you!!!
Does the measurements make any difference when its mounted on the PCB ?
That is a really good question...
Thanks dude. Very well explained without wasting any time. Is this test work on both N-channel & P-channel MOSFET???
Jameeluddin Sheikh n-channel needs a positive voltage on gate to switch on, p-channel needs negative. So I guess you just reverse the test leads.
This video is actually really good
Great Info, Thank you! But for the sake of newbies like me, you should have explained as well how come touching the Red Probe of the meter (with the meter in Diode Test Mode) to the MOSFET Gate charges it (if you get my drift, that is). Thanks again.
Nice explained 👌
very clear explanation. now I know. Keep it up. Thanx u.
Excellent demo. Thank you.
Very informational video, thank you very much for posting :)
This works because the mosfet is of a n-channel type. On a p-channel you have to switch your polarity of the multi meter.
Perfect and practical bro 👌
Hi, is this method for all types of transistors? Or just mosffets. And does it matter if its PNP or NPN? Thanks
Can these be tested in circuit? Great video.
Good, i hve been looking for something like this thank you for sharing
That was good. Thanks. A bit missing show parasite mosfet diode.
build a simple tester with an old analog meter, or even a vu meter movement. use a 9 v bat. or two in series with a resister (to limit current to full scale deflection) and red and black alligator clips. clip across collector-emitter and activate base with just a finger from base to col. Same with MOSFETs. you can actually see the transistor switch off or on with a slight brush against the gate from either drain or source. sorry, cannot easily do a video of this but a very simple analog "super ohmmeter" demonstrates transistor,fet action. Also handy to confirm leakage of capacitors that digital meters miss.
Good one. I like your explanation. Thanks for this vid.
Great video. Very clear. Cheers.
Legend..
This is how i've tested mosfets in the past. I found using the meter to charge the gate didn't work with every meter i tried.
I can't seem to get my fet to turn on .. it does have a 20-30v VGS rating though .. I'm assuming that's why, right ?
Thanks for the video ! Very nice and clear !
Yes, the meter is not putting enough voltage on the gate to turn it on. Try using three 9v batteries in series, or a power supply.
Awesome video. I have a bad power board in my LG oled tv and I suspect one or two mosfets are burnt. Gonna use your method to test those. Thanks a bunch.
So, that mosfet that you are checking is a P-channel type because the Gate is at the positive probe?Am I correct? And how to determine of what pin is the Base, Drain, and Source by using only multimeter (diode mode) amd without looking the specification of that mosfet parts?
Nice tutorial! Should I remove the mosfet before testing? or can I test it while in the PCB? Thank you!
Sancho Cabatay u should remove
This is what i needed thanks
Nice video, thanks.
What we want starts at 0:44.
Thank u for ur lessons it help me alot great work explain very clearly an simple
Thank you very much! It's really good tutorial ! I's this method worked to SFP730 transistor?
Excellent tutorial explained perfectly, thank you.
What's missing in this tutorial is identifying first the Mosfet name, it's 2sk3911.
Thanks for the video. What if I could not Identify the Source and the Drain
Can you test mosfet while it is on PCB?
Yes, just make sure there’s no power on it first
thank you so much for such great explanation.
Thank you!
Very nice awesome video. Thanks sir (Pakistan)
thanks! is it possible to test like this
with the mosfet mounted in the circuit?
Great tips thank you so much 😊 😊
Will this test work if the MOSFET is still soldered to the board?
this is the tuturial i like ...1m likes for u...
Hello,
Thank you very much for this info/tutorial. ☺
Great video! Simple and well explained....
Thank you so much, i have learnt something today.
When you detected the faulty mosfet from your tv, what symptoms was your tv exhibiting? Thanks.
Bad mosfets in the power supply usually means the TV will not turn on.
Hi is the switching action between gate and source from drain not just like a forward bias diode ie 0.5 viltage drop reading on Dmm
awesum vid.really great info and content
Thanks!
Thanks for this great tutorial.
Excellent. Is it possible for you to do a video on " THYRISTOR (SCR) Testing using a Multimeter" as well? I would really appreciate it. I thank you in anticipation.
Good stuff I have 4 blown IRFP240 where can I find them in a set ? I can only find IRFP250 will this work ?
Really informative enjoyed it
Does the mosfet must be taken out of the pcb? Or can I test the mosfet while the mosfet is still connected to the pcb?
Good tutorial
Nice thank you - does this check is equal (in what polarity concerns) to both N and P channel Mosfets?
To test P Mosfets you do the same test but swap + and - (easier to just swap them at meter and do the same test) wish someone would have mentioned that to me before spending a fair bit of cash replacing both the N and P in a amp when both were fine.
great little video.. but i can't get any readings at all no matter what connections i make . the G, D and S are the same as in your video .. i am testing a STW80NE06-10 Mosfet .. . does this mean it's completly blown ..
Can you do this when they are in circuit? Or do you have to de solder it?
This is a good start, unfortunately, a MOSFET can pass these tests and still be bad. You still need to check VF and RDS for example which can be significantly off and still pass these tests shown here.
Can an ESR tester be used to check these ?
Good video but I have a question, I have a clamp meter 266FT with no diode test mode but it has ohm test labeled 2M, 20K and continuity test labeled 200. Can I use it to test Transistors? Or I should purchase another multimeter
Thank u for your good Training
Nice video, thanks for sharing :)
Thank you for the video...great stuff.
That is: "shorted", not "shorten". Thanks for the video, very useful and informative.
HI. well explained. in very simple way. thank you very much